In one type of metal halide lamp, a pair of electrodes is provided in an arc tube, the arc tube is housed in a glass tube, and an end of the glass tube is pinch sealed. Additionally, a pin-type base is mounted on the pinch sealed portion. Such a glass tube housing the arc tube therein and sealed at an end thereof is referred to as an airtight container, and the pinch sealed portion is referred to as a pinch seal. Another type of metal halide lamp is a triple tube structure in which the airtight container is further contained in an outer tube.
A pair of connection wires electrically connected to the pair of electrodes in the arc tube extend out from an edge face of the pinch seal in parallel with an axis of the glass tube along an imaginary plane that traverses the axis of the glass tube and is parallel to a pinched surface.
The base is provided with a pair of contact pins that extend in parallel with the axis of the glass tube along the imaginary plane that traverses the axis of the glass tube and is parallel to the pinched surface. Note that the distance between the axes of the connection wires extending out from the pinch seal is equivalent to the distance between the axes of the contact pins.
The airtight container and the base are joined by inserting the pair of connection wires of the airtight container into the contact pins and pressing a predetermined portion of the contact pins in a direction orthogonal to the imaginary plane. A concavity is thus formed in a portion of the contact pins (in other words, by crimping or press bonding), electrically connecting the connection wires with the contact pins.
Note that the press is in a direction orthogonal to the imaginary plane in order to reduce manufacturing costs, since a concavity can be formed in both contact pins simultaneously (i.e. with one press) by supporting the opposite side from the location where the pair of contact pins are pressed.